Fatty acids, soya, iso-Pr esters

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

22 Sept - 20 Oct 1992

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1993

Report date:

1993

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Isopropyl palmitate

EC Number:

205-571-1

EC Name:

Isopropyl palmitate

Cas Number:

142-91-6

Molecular formula:

C19H38O2

IUPAC Name:

isopropyl palmitate

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

other: activated sludge plant secondary effluent

Details on inoculum:

- Source of inoculum/activated sludge: Secondary effluent of unacclimatised activated sludge plant at the Unilever Research Laboratory North, Great Britain.
- Preparation of inoculum for exposure: Effluent filtered through Whatman filter paper (541) to remove coarse particulate matter; DOC was reduced by sparging the filtered effluent with nitrogen after prior adjustment of the pH to 6.5

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

9.56 mg/L

Based on:

DOC

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: Mineral salts medium
- Test temperature: 19-22 °C
- pH: 6.5
- pH adjusted: yes

TEST SYSTEM
- Culturing apparatus: 160 mL hypovials containing 100 mL medium with butyl rubber septums and aluminium crimp seals
- Measuring equipment: Ionics 555 Inorganic Carbon Analyser

SAMPLING
- Sampling frequency: Day 2, 6, 10, 14, 17, 20, 24 and 28
- Sampling method: 1 hypovial per sampling removed and DIC and CO2 measured

Reference substance

Reference substance:

other: benzyl alcohol

Results and discussion

% Degradation

Parameter:

% degradation (CO2 evolution)

Value:

91.3

Sampling time:

28 d

Remarks on result:

other: 88.7-93.8 (95% C.L.)

Details on results:

The test substance degraded by > 60 % within the 10-day time window and is thus regarded as readily biodegradable.

BOD5 / COD results

Results with reference substance:

Benzyl alcohol achieved 99.1% biodegradation in 28 days and the 10-day window was fulfilled.

Any other information on results incl. tables

Biodegradability of the test substance in %:

	Biodegradability in %
Day	CAS No. 142-91-6
2	23.2
6	75.5
10	76.0
14	78.1
17	93.4
20	97.3
24	87.1
28	91.3

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable